feat: introduce a2ui-in-mcpapps sample application

.gitignore

@@ -24,3 +24,7 @@ a2a_agents/python/a2ui_agent/src/a2ui/assets/**/*.json
 agent_sdks/python/src/a2ui/assets/**/*.json
 ## Generated files for sandbox frame.
 samples/client/angular/projects/mcp_calculator/public/mcp_apps_inner_iframe/
+
+## Generated files for a2ui-in-mcpapps
+samples/agent/mcp/a2ui-in-mcpapps/server/apps/dist
+samples/agent/mcp/a2ui-in-mcpapps/server/apps/public

samples/agent/mcp/a2ui-in-mcpapps/README.md

@@ -0,0 +1,100 @@
+# A2UI in MCP Apps Sample
+
+This sample demonstrates a Model Context Protocol (MCP) Application Host that isolation-tests untrusted third-party Angular components via a secure double-iframe proxy pattern.
+
+## Architecture
+
+*   **`client/`**: The host container application (Angular). It hosts the outer safe iframe.
+*   **`server/`**: The MCP Server (Python/uv) that provides the micro-app resources and tools.
+*   **`server/apps/src/`**: The source source code for the server-hosted isolated micro-app.
+
+## Communication Flow
+
+```mermaid
+sequenceDiagram
+    participant Server as MCP Server
+    participant Host as Client Host Application
+    participant Proxy as Sandbox Proxy
+    participant App as MCP App (Sandbox)
+    participant A2UI as A2UI Surface
+
+    Note over Host: 1. Loaded from Hosting server
+    Host->>Server: 2. Fetch MCP App resource
+    Server-->>Host: Return MCP App resource
+    Host->>Proxy: 3a. Load Sandbox Proxy
+    Proxy->>App: 3b. Serve App in isolated iframe
+
+    Note over App: 4. CTA triggers relay request
+    App->>Proxy: Request tool call
+    Proxy->>Host: Relay Request
+    Host->>Server: Forward Tool Call
+    Server-->>Host: 5. Respond with A2UI JSON payload
+    Host->>Proxy: Relay payload
+    Proxy->>App: 6. Hand down payload to MCP App
+
+    App->>A2UI: 7. Renders A2UI Components
+    Note over A2UI: Click on A2UI Button
+
+    A2UI->>App: 8. A2UI Button triggers UserAction
+    App->>Proxy: Forward UserAction event
+    Proxy->>Host: Relay UserAction to Host
+    Note over Host: 9. Map Action to Tool Call
+    Host->>Server: Forward Tool Call
+    Server-->>Host: 10. Respond with A2UI payload (datamodelupdate)
+    Host->>Proxy: Relay payload
+    Proxy->>App: 11. Pipe payload to MCP App
+    App->>A2UI: Update rendering
+```
+
+---
+
+## Prerequisites
+
+- [Node.js](https://nodejs.org/) (runs the client and build scripts)
+- [Python 3.10+](https://www.python.org/) with `uv` (runs the MCP server)
+
+---
+
+## Build & Regeneration
+
+This sample relies on some generated bundle artifacts. Some are committed for convenience, while others are ignored and must be built.
+
+### 1. Build Client Sandbox Bridge
+The sandboxed iframe needs its asset bundle. Run this in the `client/` directory:
+```bash
+cd client
+npm install
+npm run build:sandbox
+```
+*(Generates `client/public/sandbox_iframe/sandbox.{js,html}`)*
+
+### 2. Rebuild the Server Hosted App (Optional)
+The server serves a bundled `app.html` artifact located in `server/apps/public/app.html`. If you modify the source code in `server/apps/src/`, you must regenerate this list:
+
+Run this in the `server/apps/src/` directory:
+```bash
+cd server/apps/src
+npm install
+npm run build:all
+```
+*(Runs Angular compilation and triggers `node inline.js` to single-file inline it into `server/apps/public/app.html`)*
+
+---
+
+## Running the Sample
+
+### 1. Start the MCP Server
+Run this in the `server/` directory:
+```bash
+cd server
+uv sync
+uv run python server.py --transport sse --port 8000
+```
+
+### 2. Start the Host Client
+Run this in the `client/` directory:
+```bash
+cd client
+npm run start
+```
+Navigate to `http://localhost:4200` to view the running host.

samples/agent/mcp/a2ui-in-mcpapps/client/.editorconfig

@@ -0,0 +1,17 @@
+# Editor configuration, see https://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.ts]
+quote_type = single
+ij_typescript_use_double_quotes = false
+
+[*.md]
+max_line_length = off
+trim_trailing_whitespace = false

samples/agent/mcp/a2ui-in-mcpapps/client/.gitignore

@@ -0,0 +1,48 @@
+# See https://docs.github.com/get-started/getting-started-with-git/ignoring-files for more about ignoring files.
+
+# Compiled output
+/dist
+/tmp
+/out-tsc
+/bazel-out
+
+# Node
+/node_modules
+npm-debug.log
+yarn-error.log
+
+# IDEs and editors
+.idea/
+.project
+.classpath
+.c9/
+*.launch
+.settings/
+*.sublime-workspace
+
+# Visual Studio Code
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+!.vscode/mcp.json
+.history/*
+
+# Miscellaneous
+/.angular/cache
+.sass-cache/
+/connect.lock
+/coverage
+/libpeerconnection.log
+testem.log
+/typings
+__screenshots__/
+
+# System files
+.DS_Store
+Thumbs.db
+
+# Generated sandbox files
+/public/sandbox_iframe/sandbox.js
+/public/sandbox_iframe/sandbox.html

samples/agent/mcp/a2ui-in-mcpapps/client/.prettierrc

@@ -0,0 +1,12 @@
+{
+  "printWidth": 100,
+  "singleQuote": true,
+  "overrides": [
+    {
+      "files": "*.html",
+      "options": {
+        "parser": "angular"
+      }
+    }
+  ]
+}

samples/agent/mcp/a2ui-in-mcpapps/client/README.md

@@ -0,0 +1,59 @@
+# Client
+
+This project was generated using [Angular CLI](https://github.com/angular/angular-cli) version 21.2.5.
+
+## Development server
+
+To start a local development server, run:
+
+```bash
+ng serve
+```
+
+Once the server is running, open your browser and navigate to `http://localhost:4200/`. The application will automatically reload whenever you modify any of the source files.
+
+## Code scaffolding
+
+Angular CLI includes powerful code scaffolding tools. To generate a new component, run:
+
+```bash
+ng generate component component-name
+```
+
+For a complete list of available schematics (such as `components`, `directives`, or `pipes`), run:
+
+```bash
+ng generate --help
+```
+
+## Building
+
+To build the project run:
+
+```bash
+ng build
+```
+
+This will compile your project and store the build artifacts in the `dist/` directory. By default, the production build optimizes your application for performance and speed.
+
+## Running unit tests
+
+To execute unit tests with the [Vitest](https://vitest.dev/) test runner, use the following command:
+
+```bash
+ng test
+```
+
+## Running end-to-end tests
+
+For end-to-end (e2e) testing, run:
+
+```bash
+ng e2e
+```
+
+Angular CLI does not come with an end-to-end testing framework by default. You can choose one that suits your needs.
+
+## Additional Resources
+
+For more information on using the Angular CLI, including detailed command references, visit the [Angular CLI Overview and Command Reference](https://angular.dev/tools/cli) page.

samples/agent/mcp/a2ui-in-mcpapps/client/angular.json

@@ -0,0 +1,71 @@
+{
+  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
+  "version": 1,
+  "cli": {
+    "packageManager": "npm"
+  },
+  "newProjectRoot": "projects",
+  "projects": {
+    "client": {
+      "projectType": "application",
+      "schematics": {},
+      "root": "",
+      "sourceRoot": "src",
+      "prefix": "app",
+      "architect": {
+        "build": {
+          "builder": "@angular/build:application",
+          "options": {
+            "browser": "src/main.ts",
+            "tsConfig": "tsconfig.app.json",
+            "assets": [
+              {
+                "glob": "**/*",
+                "input": "public"
+              }
+            ],
+            "styles": []
+          },
+          "configurations": {
+            "production": {
+              "budgets": [
+                {
+                  "type": "initial",
+                  "maximumWarning": "500kB",
+                  "maximumError": "1MB"
+                },
+                {
+                  "type": "anyComponentStyle",
+                  "maximumWarning": "4kB",
+                  "maximumError": "8kB"
+                }
+              ],
+              "outputHashing": "all"
+            },
+            "development": {
+              "optimization": false,
+              "extractLicenses": false,
+              "sourceMap": true
+            }
+          },
+          "defaultConfiguration": "production"
+        },
+        "serve": {
+          "builder": "@angular/build:dev-server",
+          "configurations": {
+            "production": {
+              "buildTarget": "client:build:production"
+            },
+            "development": {
+              "buildTarget": "client:build:development"
+            }
+          },
+          "defaultConfiguration": "development"
+        },
+        "test": {
+          "builder": "@angular/build:unit-test"
+        }
+      }
+    }
+  }
+}